National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Role of yeast WSS1 protease in DNA repair.
Adámek, Michael ; Grantz Šašková, Klára (advisor) ; Čáp, Michal (referee)
Sustaining the integrity of DNA throughout the lifetime is critical for every living organism. Therefore organisms evolved numerous ways to detect and repair different types of DNA damage caused by various endogenous and exogenous factors resulting in replication stress. Defects in these repair mechanisms can lead to severe human diseases such as neurological disorders, familial cancers or developmental syndromes. In presented master thesis, we investigated the function of a yeast protein named Wss1, a metalloprotease that participates in a recently discovered DNA repair pathway that proteolytically removes DNA-protein crosslinks. Wss1 shows strong negative interaction with another DNA repair protease, Ddi1, in which case was discovered, that double-deleted yeast strain lacking WSS1 and DDI1 is hypersensitive to hydroxyurea. Hydroxurea is a ribonucleotide reductase inhibitor that, in the end, arrests cells in the S-phase of cell-cycle. Based on previous studies, we performed rescue experiments with various deletions and single-site mutants of Wss1p to assess the involvement of particular yeast Wss1p domains in the replication stress response to hudroxyurea.
Structure and molecular mechanisms of DNA repair by Nei glycosylase
Landová, Barbora ; Šilhán, Jan (advisor) ; Lux, Vanda (referee)
Abasic sites (Ap site, from apurinic/apyrimidinic) are one of the most common lesions generated in DNA by spontaneous base loss or DNA repair processes. There are two equilibrating forms of an Ap site - ring-open aldehyde and cyclic hemiacetal. Ring- opened aldehydes are reactive electrophilic groups capable of formation covalent adduct with nucleophilic sites in DNA. DNA interstrand cross-link (ICL) resulting from the Ap sites is formed spontaneously as a covalent bond between ring-open aldehyde and amin group of adenin residue in the opposite strand of double stranded DNA. ICLs block DNA replication and transcription. The formation of Ap site derived ICL is relatively long process taking several hours. We assume that the ring-opening of an abasic site is the rate-limiting step in the formation of the thermodynamic ICL. However, formation, stability and DNA repair of Ap-ICL are still poorly understood processes. Here, I have set up mechanistic in vitro experiments to reveal and calculate the probability of Ap-ICl formation in vivo. In more detail, I study the rates of formation of Ap-ICLs in the sequence context of neighbouring nucleotides of freshly formed covalent bond of ICL. I focus on sequence preference, the influence of AT/ GC rich regions and the length of oligonucleotides. I have...
The Role of DNA Repair in the Onset and Therapy of Ovarian Cancer
Tomášová, Kristýna ; Vodička, Pavel (advisor) ; Čáp, Michal (referee)
DNA repair and DNA damage response are very important biological systems, inevitable to maintain genomic stability and fidelity of the genetic information, for the onset of ovarian cancer. Further, DNA repair is also substantially involved in the response to the therapy, since many chemotherapeutics act as DNA damaging agents. This literary analysis is intended to survay the relevance of DNA repair to ovarian carcinogenesis. Special emphasis is placed on repair defects, as it is inextricably associated with the onset of cancer and treatment outcome. Apart from well-known alternations in ovarian cancer susceptibility genes, such as BRCA1 and BRCA2 involved in homologous recombination repair, ample space will be dedicated to less common gene mutations across different repair pathways. Research confirms that abnormalities in the proteins responsible for homologous recombination repair are the leading cause of ovarian cancer. The majority of authors also suggested that targeting DNA repair pathways, especially base excision repair, can improve chemotherapy efficiency in a synergic manner. The same applies to nucleotide excision repair, which repairs platinum-DNA adducts and thus contibutes to platinum drugs resistance emerging. By way of contrast, mismatch repair in ovarian cancer is rather poorly...
Posttranslational modification of the adapter protein DAXX in the cellular response to genotoxic stress
Bražina, Jan ; Anděra, Ladislav (advisor) ; Černý, Jan (referee) ; Vodička, Pavel (referee)
Maintaining the chromosome continuity and complete genetic information in human cells is crucial for cell survival and the whole organism. It prevents life-threatening pathologies and preserves genetic continuity. However, cellular DNA is exposed to both endogenous and exogenous stress damaging its content and integrity. This stress activates mechanisms involving detection and repair of these damaged sites (DDR). One of the most serious types of DNA damage double-stranded breaks (DSB) occuring when both strands are severed. DSBs trigger wave of PTMs that regulate protein interactions, nuclear localization and catalytic activity of hundreds of proteins. Such modifications include acetylation, methylation, SUMOylation, ubiquitinylation and especially phosphorylation. The most important kinases involved in DDR kinases are ATM, ATR and DNA-PK. These kinases are activated immediately after the detection of the damaged area. DAXX (Death-associated protein 6) is an adapter and predominantly nuclear protein, which is involved in chromatin remodeling, gene expression modulation, antiviral response and depositing histone H3.3 variants into chromatin or telomeres. Daxx is essential for murine embryogenesis, since the homozygous deletion is lethal in E9.5-10. In 2006 a study mapping the substrates of kinases...
The role of 53BP1 in the cellular response to double-strand DNA breaks
Liďák, Tomáš ; Macůrek, Libor (advisor) ; Rösel, Daniel (referee)
DNA damage may result in various pathological conditions and contributes to aging and development of cancer. Evolutionarily conserved DNA damage response prevents the acumulation of mutations and protects against genomic instability. Tumor suppressor p53-binding protein 1 (53BP1) is an important regulator of the cellular response to DNA double-strand breaks (DSB) and is a canonical component of ionizing radiation-induced foci which are formed at DNA DSB following radiation exposure. Recently, new insights have been gained into its functions in the DNA damage response. Apart from its subtle role in the DNA damage checkpoints signaling, 53BP1 is a well established player in the DNA DSB repair pathway choice. The outcome of DNA repair is influenced by 53BP1 in several contexts. 53BP1 controls 5' end resection at DNA ends, improves DSB repair in heterochromatin, promotes the mobility of uncapped telomeres and mediates synapsis of DNA ends during V(D)J and class switch recombination. 53BP1 contributes to repair defect in BRCA1 (breast cancer type 1 susceptibility protein)-deficient cells, which may have an impact on the treatment of some types of breast cancer. The aim of this bachelor's thesis is to summarize new findings about the role of 53BP1 in the cellular response to DNA DSB. Powered by TCPDF (www.tcpdf.org)
Vztah mezi genetickými polymorfismy DNA reparačních genů a jejich expresí u zdravé populace (s výhledem na stanovení u onkologických pacientů).
Hánová, Monika ; Vodička, Pavel (advisor) ; Bencko, Vladimír (referee) ; Černá, Marie (referee)
DNA damage response is a complex system responsible for protection of a cell against internal and external DNA damaging agents and in maintaining genome integrity. Many of genes participating in DNA damage response pathways are polymorphic. Genetic polymorphisms in coding and regulatory regions may have impact on the function of proteins encoded by the genes. Phenotypic effect of single nucleotide polymorphisms (SNPs) is subject of investigation in connection with the ability of a cell to manage genotoxic stress and subsequently, in relation to cancer susceptibility. The aim of this thesis was to evaluate the association between SNPs in DNA repair genes (hOGG1, XRCC1, XPC) and cell cycle genes (TP53, p21CDKN1A , BCL2 and BAX) and their mRNA expression in peripheral blood lymphocytes from individuals occupationally exposed to styrene and control individuals. The aim was extended to analyses of relationships between mRNA expression levels of the above-mentioned genes and markers of exposure to styrene (concentration of styrene in blood and in air), markers of DNA damage (single strand breaks - SSBs, and endonuclease III specific sites - Endo III sites) and the base excision repair (BER) capacity, by means of γ-irradiation specific DNA repair rates and oxidative repair. Study on the group of healthy...
Implication of eukaryotic DNA repair machinery in viral replication
Hron, Tomáš ; Španielová, Hana (advisor) ; Harant, Karel (referee)
Eukaryotic DNA damage response is an important mechanism which ensures genome stability. Its components are also mobilized during viral infection as a reaction against extraneous nucleic acid. Additionally, DNA repair machinery seems to be activated by some viruses purposely to provide their replication. This activation is mediated mainly by viral proteins which are able to interact with cellular factors. In many cases, key components of DNA damage mechanisms are associated with viral replication centre and likely participate in this process. Furthermore, cellular DNA damage signaling is exploited to provide competent environment for viral reproduction. However, particular mechanisms how these cellular factors participate in viral infection are still largely unclear. In this thesis, the principles of relationship between viral infection and eukaryotic DNA damage response are summarized and main viral families which are known to activate and utilize these mechanisms for its genom replication are described.

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